AIR/FUEL - Dynojet

AIR/FUEL
FODDER
Introducing the latest
tools for datalogging
your air/fuel ratio—and
what to do with that
valuable information.
BY EVAN J. SMITH
n the current era of performance,
one of the toughest challenges for
enthusiasts and racers is tuning a
modified engine. “Tuning” refers to
the process of dialing in or
calibrating the fuel and ignition timing curves
(or maps), which allows the engine to run
with the proper air/fuel ratio under all driving
conditions. Finding the proper air/fuel ratio is
necessary in order for the engine to have the
best power, reliability, and driveability. If your
beast is experiencing lean or rich conditions,
I
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There are quite a few manufacturers selling systems to monitor and record air/fuel ratios.
The three we’ve included are the O2 Alert from Altronics, Dynojet’s Wide Band Commander,
and Innovate Motorsport’s LM-1. Each kit uses a Bosch wide-band oxygen sensor that can
accurately monitor air/fuel ratio from 9:1 to 20:1.
✦ AIR/FUEL FODDER
chances are it won’t be much fun to drive.
New-car manufacturers achieve proper
calibration only after spending millions of
dollars and thousands of man-hours testing
vehicles. They sometimes spend months or
years driving and dyno testing in various
weather conditions. And they do so for every
vehicle that rolls down the line.
Manufacturers use sophisticated and often
expensive equipment to get the best
driveability during cold start, cold and warm
idle, part-throttle cruise, and wide-open
Dynojet’s Wide Band Commander allows you
to datalog air/fuel ratio, engine rpm, and
throttle position. This kit installs easily and
retails for $530. It includes the WBC control
module, a 270-degree full-sweep electric
air/fuel gauge, a Bosch five-wire LSU4 wideband O2 sensor, an O2 harness, a multifunction cable, a power cable, a USB cable, a
sensor bung and plug, mounting hardware,
and WBC software.
Altronics’ O2 Alert can be equipped with two
oxygen sensors and includes a warning
output that helps protect against lean-out.
The basic kit includes one sensor, a USB
cable, the control box, and system software.
This kit can log engine rpm and battery
voltage. It can be upgraded with EGT
thermocouplers and two analog outputs for
pressure, flow, and position sensors.
throttle. Most vehicles are also tuned to
handle extreme circumstances such as
towing, extended periods of idling, running in
the desert, and at high altitude. Equally
important to the manufacturers is fuel
consumption, so efficiency is a big part of any
calibration.
And, after it’s all said and done, we car
nuts take these perfectly calibrated engines
and alter them, throwing on bigger intakes,
headers, different cams, forced induction,
and more. So the question then becomes,
The LM-1 has many options, but the basic
unit retails for about $349.
Altronics’ O2 Alert features this relatively
small aluminum readout box with a backlit
display. A personal computer is not needed
as the playback can be viewed on the screen,
however, the kit includes software so graphs
can be seen on your personal computer. The
warning system can activate a light, enable
fuel enrichment, shut down nitrous, or retard
the timing.
Innovate Motorsports LM-1 is one of the hottest units on the market. It has a sampling rate of 12
samples per second and can record up to 44 minutes. Installation is easy, as you can be up and
running in a matter
of minutes.
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how can you ensure your engine stays in
proper tune once it has been modified?
The solution lies in one of today’s
technologically advanced wide-band air/fuel
monitors such as Altronics O2 Alert, Dynojet’s
Wide Band Commander, or Innovate
Motorsport’s LM-1. With one of these kits the
average car guy or gal can gather the
information needed to dial-in almost any highperformance engine. And while tuning your
engine properly takes some experience, with
an understanding of fueling, ignition timing,
and ECU (or carburetor) function, you can
affordably do your own tuning.
About 20 years ago, auto manufacturers
began to employ oxygen-feedback systems
on new cars. These early systems were used
to help engines run cleaner with less
emissions resulting from combustion. As time
passed, the systems and the equipment,
namely the computers and oxygen sensors,
became better and better. Today’s cars run
very clean, and even the typical racer or hot
rodder has realized the benefits that can be
had from such a system.
Early aftermarket systems used narrowband O2 sensors that could tell only if the
engine was running right at 14.7:1 air/fuel
ratio. Therefore, it drew only a vague picture
of rich and lean. But things have changed, as
almost all the aftermarket kits now use a
wide-band O2 sensor that can chart the
air/fuel ratio between roughly 9:1 and 20:1.
Along with this, these systems use advanced,
yet affordable, logging computers so the end
user gets easy-to-use information that is
easily digested. This is important because
tuning with air/fuel data is far more accurate
than using EGT readings, or even reading
spark plugs. Best of all, the systems listed
install easily, so you can tune at the track or
on the road, as well as on the dyno.
When beginning to dial in any engine, the
tuner will want to extract the most available
horsepower and torque. He will also want to
make sure the engine remains in good
running order—in other words, he doesn’t
want it to blow up. This generally means
The Wide Band Commander uses this module
that is mounted in the vehicle. It is necessary
to use a PC to download and view the
information with this system.
Knowing the exact air/fuel ratio makes it
much easier to dial in the jetting on your
carburetor.
NEED TO FEED(BACK)
Without some type of air/fuel monitoring system, it is extremely difficult to tune forcedinduction or nitrous-equipped engines.
OCTOBER 2005 199
✦ AIR/FUEL FODDER
avoiding detonation, which is a serious killer
of high-performance engines.
Before any tuning session, be it at the
track, on the dyno, or on the street, the tuner
should also be certain the vehicle is in good
running order. This will limit any potential
problems. Next, you will need some datagathering equipment, such as one of the
air/fuel meters listed previously. Other common
tools used are exhaust gas temperature (EGT)
meters, which measure the temperature of
the exhaust gasses in the header(s), as well
as vacuum gauges and fuel-flow meters.
Fortunately, you can do almost 100 percent of
the tuning using a quality air/fuel meter.
But how do you know what the proper
actual air/fuel ratio should be? As mentioned
earlier, manufacturers began using oxygenfeedback systems on new cars some years
ago. These systems monitor the oxygen
content in the exhaust with the use of oxygen
sensors, which relay the running conditions
of the engine (rich or lean) to the engine
management computer.
The programs can add or trim the fueling of
the engine to maintain the most efficient
mixture for the given driving conditions. This
may be 15.0:1 during cruise or 12.5:1 at WOT. At
light cruise the mixture will be lean to help
achieve good fuel economy, whereas more fuel
will be added when the throttle is depressed for
acceleration. And with modern EFI, we can
fine-tune for the wide variety of driving
conditions and loads that the engine sees.
Holley offers this jet kit with a complete range
of jets.
In order to tune your fuel-injected engine, you
will need to get one of the handheld tuners or
have a chip burned for your applications.
Another way to tune
your fuel injection is
with a stand-alone
EFI system such as
this one from
ACCEL/DFI. With a
system like this you
can custom tailor all
aspects of fuel and
ignition timing for all
driving situation.
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Where carbureted engines use jets, EFI uses
fuel injectors with different flow rates. Fuel
flow can also be adjusted with fuel pressure
and/or by altering the pulse width, which is
the amount of time the injectors stay open.
✦ AIR/FUEL FODDER
IN COMMAND
While the electronics on each of the
systems is impressive, none of this would be
possible without the five-wire LSU4 Bosch
wide-band oxygen sensors. These sensors
have the ability to precisely indicate the
oxygen content in the exhaust flow. By
measuring the level of oxygen in the exhaust
flow, the sensor can relay the information and
the computer can determine how rich or lean
the mixture is.
“A typical production vehicle, along with
many of the aftermarket systems, uses
sensors that have a very narrow resolution,”
says Dan Hourigan of Dynojet. “They are
inexpensive and can tell you only if the engine
is richer or leaner than 14.7:1, but they can’t
accurately monitor and datalog the air/fuel
ratio like our system can.
“The Wide Band Commander gives you
everything you need to accurately monitor
your air/fuel ratio. In most cases, the target
air/fuel ratio for naturally aspirated engines
will be between 12.8:1 and 13.2:1, whereas
supercharged, turbocharged, and nitrousinjected engines will like a richer mixture
between 11.5:1 and 12.5:1. Each vehicle is
different, but we give you the ability to datalog
and tune based on the actual amount of air
and fuel that your engine is consuming. I’ve
found that using this equipment in
conjunction with chassis or engine dyno
testing can bring some fantastic results, but
using it at the track works well, too.”
In fact, most tuners who use a chassis
dyno rely on air/fuel datalogging to accurately
build a fuel curve for each vehicle. Road and
track testing is still a big part of it, but dialing
in the proper air/fuel ratio is what most tuners
look for when tuning for power and economy,
Most wide-band air/fuel systems rely on the
Bosch LSU 4.2 wide-band oxygen sensor.
Unlike earlier narrow-band sensors, which
knew only if the air/fuel ratio was at or near
14.7:1, the newer sensors remain accurate
from about 9:1 up to 20:1.
In order to prevent the sensor from contamination, it should be located in the top half of
the pipe. This will prevent condensation from
getting in the sensor.
At the heart of any air/fuel measuring system is the oxygen sensor. Most modern kits use a Bosch
wide-band sensor that is capable of monitoring the exact air/fuel ratio across a wide range. The
oxygen sensor will sit directly in the path of the exhaust gasses normally in the header collector
or downpipe after the exhaust manifold.
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✦ AIR/FUEL FODDER
and the chassis dyno is a great tool for that.
“In addition to measuring and recording
air/fuel, rpm, and throttle position, the Wide
Band Commander also has three
programmable relay outputs that can be used
to control a circuit based on one, two, or three
of the WBC inputs,” Hourigan says. “This
means that before the system will activate the
circuit (like a nitrous solenoid), it will look at
up to three parameters, and if they are not
met, the switch will not turn on.”
THE MODERN TUNE
As many of you know, there are a host of
hand-held tuners, highly advanced chips, and
many specialty speed/performance shops
capable of dialing in even the most serious
high-horsepower machines. And while most
of the dyno shops have some type of wideband oxygen sensor to record air/fuel ratio,
the systems are connected to the dyno and
are used in-house only. These are great if you
keep the car on the dyno, but once the car
leaves there is no way to keep track of the
air/fuel ratio in most vehicles.
But this isn’t a problem with the listed
systems because they are installed in the
vehicle. These days, tuning with air/fuel has
surpassed many of the older, tried-and-true
techniques. While measuring EGT and
reading spark plugs works on race cars that
can be run wide open and then safely shut off,
this just isn’t a feasible way to tune on the
street.
According to Hourigan, “Racers or street
enthusiasts looking for maximum performance
Many engine builders use oxygen feedback when dyno testing. You can even dyno test with one
of the listed kits and then transfer the kit to the vehicle to make sure the tune doesn’t change
from the dyno to the street or track.
Each of the kits comes with software so the information can be downloaded and viewed on
the computer.
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✦ AIR/FUEL FODDER
should be concerned with knowing the air/fuel
ratio of their engines. This is one of the most
insightful tuning tools because it can allow
you to end up with a powerful yet safe engine
tune-up.”
For every type of fuel (gasoline, methanol,
nitromethane, and so on) there’s a “perfect”
air-to-fuel ratio that will result in complete
combustion of the fuel during the combustion
cycle. When this occurs, all the heat energy
of the fuel is released and the engine is said
to be running efficiently. When gasoline is
used, this perfect ratio is 14.7:1 (but this
changes under heavy throttle load). This
14.7:1 ratio is termed the stoichiometric ratio.
Therefore, when an internal combustion
engine is running at 14.7:1, all the fuel will
theoretically be burned and optimum fuel
efficiency will be achieved.
But 14.7:1 is not the perfect ratio for all
driving conditions. For instance, idle and partthrottle cruise can withstand a leaner air/fuel
ratio upward of 15:1, but stick your foot in it
and a richer mixture such as 12.5:1 is
required. Under heavy load, such as in racing,
lean conditions can lead to misfire, a stumble,
and—at the worst—detonation. An overly
rich mixture often leads to increased
emissions and a reduction in power. You’ll
also notice fouled plugs as well as stumble
and misfire.
In the future, we plan to put these units
to the test and do some tuning. They are
the perfect tool for the self-tuner or even
for someone who just wants some extra
information.
Dynojet’s kit comes with an easy-to-read
gauge that the driver can see while on the
street or track.
SOURCES
ALTRONICS
Dept. MMFF
1411 S. Roselle Rd.
Schaumburg, IL 60193
888/464-2587
www.altronicsinc.com
DYNOJET RESEARCH
Dept. MMFF
2191 Mendenhall Dr.
N. Las Vegas, NV 89081
800/992-4993
www.widebandcommander.com
INNOVATE MOTORSPORTS
Dept. MMFF
5 Jenner, Ste. 100
Irvine, CA 92618
949/502-8400
www.tuneyourengine.com
206 www.MuscleMustangFastFords.com
Innovate’s LM-1 kit (top to bottom) can
be optioned with this LC-1 Lamda cable.
According to Innovate, “The LC-1 cable is a
complete wide-band controller built into a
sealed cable. It features the same awardwinning, patented digital measurement
principal found in the LM-1, and includes
digital input, output, and two programmable
analog outputs.”